Leveling instrument



G. G. TOWNSEND.

LEVELING INSTRUMENT.

APPLICATION HLED MAY 3. I921- RENEWED JUNE 29, 1922.

1,437,327. Patented Nov; 28, 1922.

mvmrok A TTORNE Y Patented Nata .4 pairs enonnearn i.rrwn'snnn, or FROSTBURG, MAR LAND.

' LnvELiiiiG inSTRnMnnr. 1

Application filed Maya, 1921, Serial ii i ieeser. p Renewed June 29, i922. seri ino'. 571,765.

To altwhbmtmay concern. 1

Be it known that *1, GEORGE resident of Frostburg; intlie county of Allegany, and State'of Maryland, have'invented certain new and useful Improvements in Leveling Instruments, of which the following is a specification. The present invention 'elatesgin general to surveying instruments and more particularly to an improved leveli'ng 'instrumentof the typeforming the subjectmatter of prior Patent N0.'7;5 1,723. I d

v The object of the invention is to provide a leveling instrument of'thischa'racter which is simple and durable in construction, reli able and accurate lllopratlOll, easily. and readily adpisted and controlled, andcom paratively inexpesive to manufacture which i is not impaired by variations in temperature,'

provide for convenient shipment; and which has its movable parts constrained topartake of movement wlthin proper limits and susbeing transported. v I g Other objects and advantages of the invenceptible of being locked in position when tion reside in certain novel features of con struction, combination and arragemeiit of parts which'will be hereinafter, morefully described and particularlypo'inted out in the appended claims, reference being had to the accompanying drawings forming'p'art of this specification, and in which:

Figure 1 is aneelevational view of the invention, the staff being broken away;

Figure 2 is asimilai' View in longitudinal section; i

Figure 3 is a top plan view thereof; f

15 Figure 4 is an elevational view of one end ofthe sight tube; i d i Figure 5 is a fragmentary view in horiZon-' tal section of the sight tube Figure 6 is a detail" V1GW: n section of the friction stops forthe latch; and

Figure 7 is an elevational View of the 1 complete instrument.

Referring to the drawings wherein forthe sakeof illustration is shown the preferred I GrALE Town- SEND, a c tizen ofthe' llnited States and a;

in mining work; which 'hasits sighttube so embodiment ofth e' invention, the numeral 10 desig'natesa supporting staff provided with a slot ll-adj acent to the upper end thereof and having a head 12 at the upper end and ex tending across the slot. The head 12 andthe staff are f of one piece and preferably are constructed of wood. :Metallic side plates 13 are suitably secured, as by screws 14:, to the side faces of the staffadjacent the upper end thereof-and extend acrossthe side faces of the head 12. Metallic reinforcingplates 15 1 and 16 are inset in suitable saw cuts providedtherefor in the head 12 and extend at, right-angles to the side plates 13 and abut these side plates attheir ends,-the plates 15 and 16. being arranged in spacedand parallel relation with respect to each other. Suitable fastening means is provided for maintaining the plates in positionjand preferably consists of a plurality of nails 1 or pins 17 driven through the head and extending through" suitable openings drilled in the metallic 'plates'15 and 16. The head 12-is severed transversely and a filling F of elastic material such asbees wax and rosin or similar substa'nceisarranged between the severed portions of the head. i

A spindle 18 is rotatably'inounted within" the staff by-jmeans of trunnions 19 carried v thereby and rotatably journaled in the side plates 13. A sight tube support designated generally at 20 is mounted upon the spindle I 18. i This sight tube support comprises a metallic frame which maybe'ca stor wrought asdesired and which if'wrought, includes overlapping sections 21 and 22 having alined openings 23 receiving the spindle 18 and tube. The frame also includes a depending A sight tube 30 is mounted in the seat 24.

if "of the sighttube support and is retained in position therein by means of a set screw 31 threaded through the sections 21 and 22 of the frame and extending through a transhaving a seat 2 1 adapted to 'receive the sight verse opening of the spindle and having its pointed end '31 engaging the outer 'wall of The head'12 is"provided" the sight tube. above the set screw 31 with 'anopening 12 affording access to the slot of the screw whereby it may be manipulated by a screw driver or other suitable instrument. By-

thus mounting the sight tube 30 it is obvious that while it is properly and securely supported in position when the set screw is turned home nevertheless it may be readily disassembled to provide for convenient shipment of the instrument by merely loosening the screw 31 and withdrawing the sight tube from its seat 2%. It is to be noted that the set screw 31 also serves to lock or secure the frame to the spindle.

A sighting device, designated generally at-34, is arranged within and'near one end is provided a" V-shaped notch lfZ- ,-the apex ing 26 of the sight tube supportby meansof the pendulum;

of the sight tube, and a coact-ing sightingdevice, designatedv generally at 35, is arranged within and near the other end of the sight tube and is oppositely arranged with. respect to; the first-named sighting device. Both of the sighting devieesare of identical construction, though oppositely. arranged and each includes a flatring 36 which: engages the inner wall of the sight tube 30,

and is suitably secured thereto, an opaque semi-circular diaphragm 37 carried by the flat ring 36 and having-a peep-holeBStherein and a cross wire 39 which extendshorizontally' of. the sighting device and has one end secured t'o' the ring'36,.as'at 40, andthe other end secured to the semi-circular diaphragm, as at 412. At the intersection of the cross wire and the vertical linepresented by the edge of the diaphragn there of which lies on the cross wire.

A wei 'ht 5O constitutln a Jendulum 1s fixed to the lower end of the rod 51, which in turn is mounted upon. the pivot bearof a pivot pin 52. An adjusting screw 53 is carried by a threaded bearing 5.4L providedtherefor in the frame and abuts at its inner end a reduced and flattened portion 51 provided atthe upper end or the rod 51 and this adjustingscrew together with an opposing spring 55 constitutes a means whereby the pendulummay be adjusted: when necessary. It isto be notedthat the pendulum 50- is freely suspended upon theside platesl3-by means of the frame, trunnions and spindle, and that the pendulum thereby controls the sight tube support and 'consequently the sight tube itself. I

Means is provided for locking the pen dulum in position against vibration an'd preferably includes a pivoted latch bar 56" friction-head (SQ-whichis engageable' with the adjacent side of the slot and is urged into frictional engagement therewith by means of a coil spring 64: disposed in the barrel and urging the friction head out wardly and against the wall of the slot. The latch bar is thus maintained in any position" to which it may be adjusted but it is not absolutely held against movement for the operator may easily apply a suf- -ficient force to the latch bar to move its look lug 57 into and out of engagement with the recess of the pendulum 58.

Stop lugs 65 are carried bythe pendulum and coact with the lock lug 57 when the latch bar is in open position to limit the amplitude of the vibration or the swing of the pendulum, thus preventing excessive swing and consequent injury or distorti n of the parts. A wind guard 66-1nay be provided if desired.

In use, the staff is grasped below the weight and held in approximately vertical position. The sight tube under the influence of the penduluin' will then instantly assume a horizontal position and the sight can then readily be taken. Under ordinary conditions sight is taken through the peephole 38- and on the cross wire 39 but it may be taken by means of the peep-hole and one of the notches. 42 and when the light is badthis is preferred as-these are operable for sighting purposes even in very poor light or when. artificial illumination is made use of. The staff can be easily turned to present one or the other endsof the sight tube to the eye to take the sight or effect adjustment. It is to be noted that adj ustment may be readily made by manipulat ing the adjusting screw The'trunnions and sideplates provide a delicate yet strong suspension: for the pendulum and this suspension is not impaired by variations in the temperature as the construction of the head precludes movement of the side plates toward and away from each other and particularly toward each other which latter movement would be liable to bind the suspension and preclude easy operation.-

The latch bar and its lock lug provide ready means for locking the pendulum against vibration when it is being transported, and this together with the demountable sight tube provide an instrumentof this character which may be readily packed for shipment.

As shown in Figure 7, the staff 10 may, it desired consist of sections det-achably secured together with a construction of this character the height of the staff may be varied and thus the staff may be adapted to, various uses and particularly it may be adapted for use in low workings in mines.

I claim:

1,111: a leveling. instrument, a staff having a slot therein adjacent the upper end head, metallic reinforcing plates inset in the head and abutting the side plates,said head being severed transversely, a filling of elastic material between said severed portions, a spindle having trunnions rotatably journaled in said side plates, a sight tube support comprising a frame carried by said spindle and having a seat adapted to receive a sight tube and a depending extension, a sight tube arranged in the seat of said frame, sighting devices in said sight tube, common means for securing the frame to the spindle and for securing the sight tube in its seat, a pendulum, a rod carrying the pendulum at its lower end, means for pivotally mounting the rod within the extension of the frame, an adjusting screw engaging the upper end of the rod, an opposing spring for said adjusting screw, a latch bar pivoted to the staff and having a lock lug, said pendulum having a recess adapted to receive said lock lug, means carried by the latch bar for maintaining it in adjusted position, and stop lugs carried by the pendulum and cooperable with the lock lug to limit the movement of the pendulum.

2. In aleveling instrument, a staff having a slot therein, a spindle, a sight tube support comprising a frame carried by said spindle and having a seat adapted to receive a sight tube and a depending exten sion, a sight tube arranged in the seat of said frame, sighting devices in said sight tube, common means for securing the frame to the spindle and for securing the sight tube in its seat, a pendulum, a rod carrying the pendulum-at its lower end, and means for pivotally mounting the rod within the eX- tension of the frame, an adjusting screw engaging the upper end of the rod, an oppos ing spring for said adjusting screw, a latch bar pivoted to the staff and having a lock lug, said pendulum having a recess adapted to receive said lock lug, means carried by the latch bar for maintaining it in adjusted position, and stop lugs carried by the pendulum and cooperable with the lock lug .to limit the movement of the pendulum.

3. In a leveling instrument, a staff having a slot therein adjacent the upper end the cot", head at the upper end of the staff, side plates secured to the staff and to the head. metallic reinforcing plates inset in the head and abutting the side plates, said head being severed transversely, a filling of elastic material between said severed portions, a spindle havin trunnions rotatably journaled in said side plates, a sight tube support comprising a frame carried by said spindle and having a seat adapted to receive a sight tube and a depending extension, a sight tube arranged in the seat of said frame, sighting devices in said sight tube, common means for securing the frame to the spindle and for securing the sight tube in its seat, a pendulum, a rod carrying the'pendulum at its lower end, and means for pivotally mounting the rod upon the extension of the frame.

4t. In" a leveling instrument, a staff having a slot therein adjacent the upper end thereof, a head at the upper end of the staff,

side plates secured to the staff and to the head, metallic reinforcing plates inset in the head and abutting the side plates, said head being severed transversely, a filling of elastic material between said severed portions, a spindle rotatably journaled in said side plates, a sight tube support carried by the spindle, a sight tube carried on said support, and a pendulum controlling said sight tube support.

5. In a leveling instrument, a stafi having a slot therein, a spindle rotatably journaled on said staff, a frame carried by said spindle and having a seat, a sight tube supported on the seat of said frame and common means for securing the frame to the spindle and for securing the sight tube in its seat.

6. In a leveling instrument, a staff, a sight tube support pivotally mounted in said staff, a sight tube carried by said sight tubesupport, a pendulum controlling said sight tube support, a latch bar pivoted to the staff and having a lock lug, said pen-.

dulum having a recess adapted to receive said lock lug, means carried by the latch bar for maintaining it in adjusted position,

and stop lugs carried by the pendulum and cooperable with the lock lug to limit the movement of the pendulum.

7. In a leveling instrument, a staff, a sight tube support pivotally mounted on said staff, a sight tube carried by said sight tube support, a pendulum controlling said sight tube support, a latch bar pivoted to the staff and having a lock lug, said pendulum having a recess, adapted to receive said lock lug and means carried by the latch bar for maintaining it in adjusted position.

8. In a leveling instrument, a staff, a sight tube support suspended within said staff, a sight tube carried by said sight tube support, a similar sighting device arranged near each. end of said sight tube and including a flat ring, an opaque semi-circular diaphragm having a peep-hole therein, and a cross wire secured at one end to said ring and at the other end to said diaphragm, said diaphragm having a V-shaped notch therein having its apex coincident with said cross wire.

9. In a leveling instrument, a sighting device including a flat ring, an opaque semicircular diaphragm having a peep-hole therein and a cross wire secured at one end to said ring and at the other end to said diaphragm, said liaphragm having a l-slmped notch therein having its apex ceineident with said cross Wire.

10. A leveling instrument, a staff halving a head and having a slot therein, adjacent the upper end thereof, side plates secured to the staff and to the head, metallic reinforcing plates carried by said head, said head being severed transversely, a filling of elastic material between said severed portions a spindle rotutubly journaled in said side plates, a sight tube support carried by thespindle, a sight tube carried on said support and a pendulum controlling said sight tube support.

GEORGE GALE TOXVNSEND; 

